Sofa



FIG. 1 is a front perspective view of a sofa showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a left side elevation view thereof; and,

FIG. 4 is an enlarged front perspective view of a portion of FIG. 1.

Views of the sofa not shown in the figures form no part of the claimed design.

The dashed broken lines depicting portions of the sofa represent boundaries of the claimed design and form no part thereof.

The dot-dash broken lines in the figures represent a boundary line that forms no part of the claimed design. 

CLAIM The ornamental design for a sofa, as shown and described. 